Sample collection and delivery apparatus

ABSTRACT

A syringe type sampling valve wherein delivery is achieved by rapid drive forward of syringe piston and collection of sample is achieved by the cam controlled with drawal of the piston. The cam assures slow, usually uniform filling rate of the syringe barrel.

United States Patent [191 llargash et a1.

[451 Nov. 19, 1974 SAMPLE COLLECTION AND DELIVERY APPARATUS [75]Inventors: Paul Hal-gash, Saginaw; Franklin .1.

Karle, Midland, both of Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

[22] Filed: Aug. 2, 1972 21 Appl. No.: 277,318

[52] US. Cl. 73/4256, 23/259, 73/422 R [51] Int. Cl. G0ln 1/14 [58]Field of Search 73/4254 R, 423 R, 425.6,

[56] References Cited UNITED STATES PATENTS 7/1959 Alm 141/130 4/1965Anthon 23/253 R 6/1965 Peterson et a1. 73/4254 R Primary ExaminerRichard C. Queisser Assistant Examiner-Daniel M. Yasich Attorney, Agent,or Firm-E. D. Ayers ABSTRACT A syringe type sampling valve whereindelivery is achieved by rapid drive forward of syringe piston andcollection of sample is achieved by the cam controlled with drawal ofthe piston. The cam assures slow, usually uniform filling rate of thesyringe barrel.

6 Claims, 2 Drawing Figures TIMER F; 7

SAMPLE COLLECTION AND DELIVERY APPARATUS BACKGROUND OF THE INVENTIONThis invention relates to sampling valve apparatus, and particularly tosuch apparatus wherein a syringe barrel and piston coupled to a suitablevalving unit are used to withdraw sample from one source and thendischarge the sample to another utilization line or the like.

Other syringe type sampling valve assemblies are known, but most areworn or other gear type load and discharge devices.

It is an object of this invention to provide an im proved sampling valveassembly which is adapted to a controlled sample loading rate andwherein rapid discharge of sample from the assembly may be accomplished.

OBJECTS OF THE INVENTION A further object of the invention is to provideimproved sample valve apparatus wherein discharge of sample may beaccomplished at any time during the sample withdrawal cycle withoutaffecting the sample withdrawal apparatus.

STATEMENT OF INVENTION In accordance with this invention, there isprovided apparatus wherein the needle end of a syringe is coupled to asample material inlet and discharge unit. The barrel of the syringe isheld in fixed position while the piston is withdrawn by the force of aspring which is first compressed by the operation of the discharge cycledrive means, usually an air cylinder, for example, driving a rod coupledto the piston.

The loading rate of the syringe barrel is controlled by the contactingof a stop element coupled to the rod against the peripheral surface of arotating cam. Usually the shape of the cam is such that a constantbarrel loading rate is achieved. As material is discharged from thebarrel, the stop element leaves the cam and moves to a forward positionand is held there until further cam rotation indexes with the stopelement and air from air drive means for the rod element is released.Filling of the barrel then starts as the spring force withdraws thepiston.

BRIEF DESCRIPTION OF THE DRAWING The invention, as well as additionalobjects and advantages thereof, will best be understood when thefollowing detailed description is read in connection with theaccompanying drawing, in which:

FIG. 1 is a side elevational view of sampling valve apparatus inaccordance with this invention, and

FIG. 2 is a plan view of the apparatus shown in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWING Referring to the drawing, there isshown apparatus, indicated generally by the numeral 10, for samplematerial withdrawing and discharging. The apparatus is supported on andby a base plate 12 fixedly coupled to end plates 14, 16.

A syringe barrel [8 is held in a fixed generally horizontal positionwith respect to the base plate 12 by means of the holding block 20 whichsurrounds the barrel and is secured to the base plate 12.

The needle 68 is coupled between the forward end of the barrel 18 and asample material inlet-outlet valved unit 66.

A pneumatic piston device 28 driving a rod 26 is fixedly coupled to theend plate 14 so that the rod 26 is axially aligned with the piston 22 inthe syringe barrel 18. The device 28 includes a coil spring 29surrounding the part of the rod 26 disposed within the housing of thedevice 28, the ends of the spring bearing respectively against theforward end of the housing and a piston 31 attached to the rear end ofthe rod 26.

The forward end of the rod 26 is coupled to the rear end of the syringepiston 22 by means of the coupling collar 24.

A rod-like member 36 carrying a rotatable stop or cam contacting element33 is coupled to and extends downwardly from the collar 24. The lowerend part of member 36, containing a sliding contacting element 34, ridesin a slot 32 in the base plate 12. The slot 32 is aligned with andatleast coextensive with the length of travel of the piston 22.

A generally cardioid shaped flat cam or cam-like plate element 38 isfixedly eccentrically coupled to a shaft 40 whose reduced diameter lowerpart extends through the base plate 12 and has a worm gear plate 42coupled thereto.

The gear plate 42 is driven by the worm element 44 on rotatable shaft48. The shaft 48, supported by bearings 46, 50 coupled to the base plate12 and end plate 14, respectively, extends through the end plate 14 andis coupled through gears 52, 54 to a drive motor 56 which is coupled tothe end plate 14.

The shaft 40 is located beneath the rod 26, the longitudinal axis of theshaft 40 perpendicularly intersecting the longitudinal axis of the rod26. The cam-like plate 38 is positioned so that as it rotates, thecam-like plate element is aligned with the cam contacting element 33 andpasses under the pneumatic piston device 28.

The cam-like plate element 38 has a rod-like indexing element 45 on itsupper surface. A micro-switch 60 is secured to the base plate 12 and hasits contact 61 extended over the top of the cam 38 so that it contactsthe indexing element 45 each time the cam rotates. The position of theindexing element 45 is such that contact with contact 61 occurs when theedge of the cam contacts the cam contacting element 33 at the mostforward position of the piston 22.

A micro-switch 62, coupled to base plate 12, has a feeler contact arm 63extending therefrom so that the switch is actuated when the piston 22 isin its most forward position (the arm 63 contacts the collar 24).

A micro-switch 58, coupled to base plate 12, has its contact arm 59positioned so that the switch is actuated by the forward movement of thepin 57 extending from the valved unit 66.

Air is supplied to the device 28 through tube 30 coupled to the valve64, commonly a three way valve. Operation 7 In operation with the barrel18 full of sample, a timer 100, a simple cam actuated timer, operatesthe valve 66, pushing the rod 57 outwardly to actuate microswitch 58.The closing of micro-switch 58 operates air valve 64 to supply air tothe device 28, rapidly pushing the rod 26 forward to advance piston 22and empty the barrel 18 of sample material.

As the rod 26 reaches its most forward position to empty the barrel 18,arm 63 of micro-switch 62 contacts the collar 24, actuating the switch62 to close the valve 66, thus withdrawing the pin 57 so microswitch 58is de-actuated.

The timer 100 is connected to a power supply 102. The electrical wires Athrough F of the timer 100 are shown in FIG. 2 as being connected to thecorresponding wires A through F of the elements therein. The timermaintains air pressure through valve 64 on the device 28 until therotation of the cam 38 is such that the pin 45 actuates the switch 60which shuts off the motor 56 with the cam 38 contacting the stop element33. The air is then released from the device 28, allowing the compressedspring 29 to tend to draw back the rod 26. The rod 26 cannot move,however, because the stop element 33 bears against the edge of the cam38.

When sample is to be withdrawn through the closed valve unit 66, thetimer starts the worm drive motor 56, causing the cam to rotate andpermitting the piston 22 to be drawn back at a slow rate.

By the time the cam has rotated 180 degrees the syringe barrel is filledand the timer may then cause valve 66 to open to re-start the dischargecycle as previously described. 8

When the cam 38 has a configuration such that a constant barrel fillingrate is achieved, the timer may be adjusted to fill the barrel to anypredetermined amount, if desired.

The shape of the cam 38 may vary widely from tha shown. For example, asshown in FIG. 2, only the left hand lobe of the cam is used to controlloading of the barrel if the cam rotates in a clockwise direction.Symmetry of the cam permits rotation of the cam 38 in either direction,however, to accomplish loading of the barrel 18.

The slow rotation of the cam 38 permits the barrel to be filled withoutthe usual introduction of bubbles to the barrel, thus providing auniform rate of input to the barrel.

Further, this apparatus permits the discharge of sample material at anytime during the filling cycle since there is no fixed coupling betweenthe cam 38 and the rod 26.

While a spring loaded pneumatic cylinder 28 has been described, a doubleacting pneumatic cylinder,

solenoid driven piston device or other suitable drive and withdrawalmeans may be used. The motor 56 may be chosen for any wanted operatingspeed. Sample vis' cosity variations may require changes in motor speedand/or gears to provide a suitable barrel filling rate.

What is claimed is:

l. Fluid sample withdrawal and discharging apparatus comprising asyringe-like hollow barrel having a close fitting piston therein, saidbarrel having a constricted forward end and an open rear end, saidpiston extending into said barrel from said rear end, means including anactuating rod-like member for rapidly driving said piston towards saidconstricted forward end and for withdrawing said piston away from saidconstricted end, a rotatable cam-like plate having an edge surface,means for rotating said cam-like plate, said cam-like plate beingdisposed adjacent to said rod-like member, contact means coupled to saidrod-like member and positioned to bear against said edge surface of saidcam as said piston is withdrawn away from said constricted end, andtiming means cooperating with switching means selectively to actuatesaid means for driving said piston and said means for rotating saidcam-like element.

2. Apparatus in accordance with claim 1, wherein said means for drivingsaid piston forward and for withdrawing said piston comprises a springloaded pneumatic cylinder device coupled to said rod-like member.

3. Apparatus in accordance with claim 1, wherein said cam-like plate isdisposed under said rod-like member and said contact means comprises arotatable element coupled to a rod extending downwardly with respect toand is coupled to said rod-like member.

4. Apparatus in accordance with claim 1, wherein means is provided toprevent rotation of said rod-like member.

5. Apparatus in accordance with claim 1, wherein said cam-like plate iscoupled to a shaft rotatably driven by worm drive means.

6. Apparatus in accordance with claim 1, wherein means are provided forpositionally indexing said camlike plate with respect to said pistonwhen said piston is in most forward position towards said constricted

1. Fluid sample withdrawal and discharging apparatus comprising asyringe-like hollow barrel having a close fitting piston therein, saidbarrel having a constricted forward end and an open rear end, saidpiston extending into said barrel from said rear end, means including anactuating rod-like member for rapidly driving said piston towards saidconstricted forward end and for withdrawing said piston away from saidconstricted end, a rotatable cam-like plate having an edge surface,means for rotating said cam-like plate, said cam-like plate beingdisposed adjacent to said rod-like member, contact means coupled to saidrod-like member and positioned to bear against said edge surface of saidcam as said piston is withdrawn away from said constricted end, andtiming means cooperating with switching means selectively to actuatesaid means for driving said piston and said means for rotating saidcam-like element.
 2. Apparatus in accordance with claim 1, wherein saidmeans for driving said piston forward and for withdrawing said pistoncomprises a spring loaded pneumatic cylinder device coupled to saidrod-like member.
 3. Apparatus in accordance with claim 1, wherein saidcam-like plate is disposed under said rod-like member and said contactmeans comprises a rotatable element coupled to a rod extendingdownwardly with respect to and is coupled to said rod-like member. 4.Apparatus in accordance with claim 1, wherein means is provided toprevent rotation of said rod-like member.
 5. Apparatus in accordancewith claim 1, wherein said cam-like plate is coupled to a shaftrotatably driven by worm drive means.
 6. Apparatus in accordance withclaim 1, wherein means are provided for positionally indexing saidcam-like plate with respect to said piston when said piston is in mostforward position towards said constricted end.